Heretofore, in vehicle seat devices, there is one which employs a seatback divided in the vertical direction and which employs a center bending mechanism in which an upper-side frame being a frame constituting an upper-side section thereof is tiltable independently of a lower-side frame being a frame constituting a lower-side section (Patent Document 1). The center bending mechanism in the vehicle seat device is a device which brings about a tilting motion at a hinge portion directly coupling an upper end portion of the lower-side frame and a lower end portion of the upper-side frame, and a rotational center in tilting the upper-side frame exists in the hinge portion.    Patent Document 1: JP2007-6948 A1 (refer to paragraph 0002, embodiment, FIG. 1 and the like)